1fo6
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(New page: 200px<br /><applet load="1fo6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1fo6, resolution 1.95Å" /> '''CRYSTAL STRUCTURE AN...)
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Revision as of 12:57, 20 November 2007
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CRYSTAL STRUCTURE ANALYSIS OF N-CARBAMoYL-D-AMINO-ACID AMIDOHYDROLASE
Overview
The N-carbamoyl-D-amino-acid amidohydrolase (D-NCAase) is used on an, industrial scale for the production of D-amino acids. The crystal, structure of D-NCAase was solved by multiple isomorphous replacement with, anomalous scattering using xenon and gold derivatives, and refined to 1.95, A resolution, to an R-factor of 18.6 %. The crystal structure shows a, four-layer alpha/beta fold with two six-stranded beta sheets packed on, either side by two alpha helices. One exterior layer faces the solvent, whereas the other one is buried and involved in the tight intersubunit, contacts. A long C-terminal fragment extends from a monomer to a site near, a dyad axis, and associates with another monomer to form a small and, hydrophobic cavity, where a xenon atom can bind. Site-directed mutagenesis, of His129, His144 and His215 revealed strict geometric requirements of, these conserved residues to maintain a stable conformation of a putative, catalytic cleft. A region located within this cleft involving Cys172, Glu47, and Lys127 is proposed for D-NCAase catalysis and is similar to the, Cys-Asp-Lys site of N-carbamoylsarcosine amidohydrolase. The homologous, active-site framework of these enzymes with distinct structures suggests, convergent evolution of a common catalytic mechanism.
About this Structure
1FO6 is a Single protein structure of sequence from Agrobacterium tumefaciens with XE as ligand. Active as Gamma-glutamyl hydrolase, with EC number 3.4.19.9 Full crystallographic information is available from OCA.
Reference
Crystal structure and site-directed mutagenesis studies of N-carbamoyl-D-amino-acid amidohydrolase from Agrobacterium radiobacter reveals a homotetramer and insight into a catalytic cleft., Wang WC, Hsu WH, Chien FT, Chen CY, J Mol Biol. 2001 Feb 16;306(2):251-61. PMID:11237598
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